uac is ok for IT people however its pointless for users as they will always click on OK to what ever warning popsup and so still get infected
The elevation dialog aspect of User Account Control is not for security purposes, they're a convenience to enable users to run with standard user rights. UAC is a step to shift the Windows environment from an administrative based model over to a standard user one. Before Windows Vista came out, everyone was basically running as an administrator, since that was the default in Windows, and this resulted in software being designed for that administrative model. This is something that needed to change.
As of Windows Vista, due to the implementation of User Account Control, when you log into the initial account which is created upon installation, referred to as a Protected Administrator, you run in a mode called Administrator Approval Mode and are given two tokens, one with standard user rights and the other with administrator rights. The standard user token is used by default. This means that everyone now appears as if they are standard users from a software developers perspective which encourages them to write their applications so they work correctly with standard user rights and don't unnecessarily require administrator rights.
Whilst running as a Protected Administrator is securer than running as an administrator, the security benefits are merely a side effect of the primary purpose of the Protected Administrator account, which as said above is to encourage software developers to write their applications so they work correctly with standard user rights. If you're interested in moving over to a standard user account in the future, then using the Protected Administrator account is a nice first step towards that goal.
UAC's real value is enabling users to take advantage of a security feature i.e. standard user accounts, primarily due to the elevation dialogs. When ever the user wishes to perform an administrative based operation, instead of having to switch to an administrator account, they will be able to do that operation on the fly by entering the credentials of an administrator user into the over the shoulder elevation dialog. Whilst the latter isn't quite as secure as the former, since elevation always introduces an insecurity to the system, it is much better than the alternative of users running as an administrator all the time, which would happen if users had no other way of accessing administrator rights other than switching accounts.
Some reading material:
Inside Windows Vista User Account Control - Mark Russinovich
Inside Windows 7 User Account Control - Mark Russinovich
Security Features vs. Convenience - Jim Allchin
PsExec, User Account Control and Security Boundaries - Mark Russinovich
